1. Field of the Invention
The invention relates to an electrical connector, and more particularly to an electrical connector for bidirectionally electrical connections.
2. Related Art
The universal serial bus (USB) is the most popular signal transmission specification in the modern computer apparatus. The connector socket and the transmission cable satisfying this specification can make the peripheral apparatus, such as a mouse, a keyboard or the like, which is externally connected to the computer, be immediately plugged and played.
At present, the USB 2.0 and USB 3.0 specifications are used. As shown in FIG. 1, the conventional USB 2.0 male plug 90 includes a plastic base 91 and a metal housing 92. The metal housing 92 covers the plastic base 91, and a connection space 93 is formed between the metal housing 92 and the plastic base 91. Only one surface of the plastic base 91 is formed with one row of connection points 94 exposed to the connection space 93. At present, the specifications specified by the USB Society are listed in the following. The overall height “i” is equal to 4.5 mm, the half height “j” corresponding to the connection space 93 is equal to 2.25 mm, and the height “k” of the connection space is equal to 1.95 mm.
At present, one surface of the tongue of the USB 2.0 socket has one row of connection points. In use, the USB 2.0 plug has to be correctly inserted so that the connection points of the plug and the socket can be aligned and electrically connected together. In order to ensure the electrical connection to be established when the USB plug is inserted, mistake-proof designs, as shown in FIG. 1A, are provided on the socket and the plug. The normal direction corresponds to the mark 97, formed on one surface of the handle 96 connected to the USB 2.0 male plug 90, facing upwards. At this time, the connection point 94 faces upwards. When the plug is inserted in the normal direction, the plug can be electrically connected to the socket. As shown in FIG. 1B, the USB plug cannot be reversely inserted into the socket, so that the electrical connection after the insertion can be ensured. The user usually randomly inserts the plug into the socket, so the possibility of failing to insert the plug is equal to ½. So, the user usually has to insert the plug twice, and the inconvenience in use is caused.
As shown in FIG. 2, the conventional USB 2.0 socket 80 includes a plastic base 81, a metal housing 83 and one row of terminals 87. The front end of the plastic base 81 is integrally formed with a horizontally extending tongue 82. The metal housing 83 is positioned at the front end of the plastic base 81 to form a connection slot 84. The tongue 82 is located at the lower section of the connection slot 84. The one row of four terminals 87 is fixed to the plastic base 81, extends frontwards and is arranged on the tongue 82. A projecting connection point 88 is formed near a distal end of the terminal 87.
In order to match with the mistake-proof design of the male plug, the USB socket 80 has the following dimensions. The height “o” of the connection slot is equal to 5.12 mm; the thickness “p” of the tongue is equal to 1.84 mm; the height “s” above the tongue is equal to 0.72 mm; and the height “q” below the tongue is equal to 2.56 mm. Thus, the USB 2.0 male plug 90 has to be inserted with the connection point 94 facing downwards, so that the connection space 93 and the tongue 82 are fit and positioned with each other. The half height “j” (2.25 mm) is fit with the height “q” (2.56 mm) below the tongue. The reverse USB male plug 90 cannot be inserted. In addition, the horizontal distance “t” from the insert end 86 of the positioning plane of the connection slot 84 to the first connection point 88 of the first terminal is equal to 3.5 mm.
When the USB 2.0 male plug 90 is inserted into the USB socket 80, the plug 90 and the socket 80 are tightly fit with each other according to the height “k” (1.95 mm) of the connection space and the thickness “p” (1.84 mm) of the tongue.
As shown in FIG. 2A, the conventional USB 3.0 socket 85 has the structure and associated dimensions, which are substantially the same as those of the USB 2.0 socket 80 except that the tongue 82 of the USB 3.0 socket 85 is longer and the front section thereof is formed with one row of five second connection points 89, which cannot be elastically moved. In addition, the horizontal distance “t” from the insert end 86 of the positioning plane of the connection slot 84 to the first connection point 88 of the first terminal is equal to 4.07 mm.
The structure and the associated dimensions of the USB 3.0 male plug are substantially the same as those of the USB 2.0 socket 80 except that the USB 3.0 plug additionally has one row of five connection points, which project beyond the connection space and can be elastically moved.
The conventional USB socket, either the USB 2.0 or 3.0 socket only has the contact pattern formed on one single surface, and thus cannot allow the bidirectional insertion and connection. However, if the USB socket is designed to allow the bidirectional insertion and connection, the connection points of the terminals have to be formed on two surfaces of the tongue, the positioning of the bidirectionally inserted USB male plug has to be ensured, and the four terminals 87 cannot be short-circuited. When the USB male plug is inserted and its metal housing touches the connection points 88 of the terminals 87 on one surface of the tongue, the short circuit is caused to damage the USB socket. Due to the above-mentioned problems, the manufacturers have encountered the bottleneck in developing this product.
The applicant has paid attention to the research and development of the bidirectionally inserted and connected USB socket and finally provides the improved structure to overcome the above-mentioned problems and the pattern of the tongue for the USB 3.0 socket.